This invention relates to the process of applying a water-repellent material to leather game balls such as American-style footballs and rugby balls.
Premium game-quality footballs are made with a steerhide leather cover, not pigskin as often believed. Because of the beating that a football receives in a game, leather has proven to be a very durable material to use due to its intertwining fiber structure. The intertwining of the leather's fibers gives the material flexibility and strength.
For superior aerodynamics and grippability, football leather is formed with a pebbled surface. Along with the pebbled surface, football leather should have a tacky finish that gives the ball a good feel for gripping while throwing or catching the football.
With all of the foregoing in mind, tradition also plays an important part in the use of leather in game-quality footballs.
For American-style leather footballs, one company--Horween Leather Company of Chicago, Illinois--is considered to make the finest football leather in the world. Horween's football leather is tanned from 100% steer hides. The tannage is initially of a chrome type and is followed with a vegetable retannage. The leather is finished with a brown-red analine dye to give the leather its classic color along with a clear nitrocellulose topcoat to give the leather a scuff-resistant surface.
The key to the leather is its tanned-in tack, which greatly aids in the performance and feel of the football. This tack material is proprietary to Horween. The tanned-in tacky feel provides a maximum amount of gripping aid without causing the football to be too sticky, which could result in release problems when throwing the ball. Because this leather has been the material of choice by both professional (National Football League) and amateur (NCAA and Federation of National High School Athletics) football organizations, changing this leather could affect the outcome of the game.
Tradition is another important aspect of the game. Although the physical properties of a football--such as color, size, weight, feel, and performance--are specified by the above-mentioned governing bodies, these specifications have been created by the long-standing traditions since the introduction of the sport. Although leather has been used since the inception of the game, it is still the preferred material over synthetic materials even though leather has certain shortcomings.
Traditionally, football is played during the fall season when the weather becomes cold and rainy. A major shortcoming of the leather football has been that leather absorbs water when it becomes wet. In fact, leather is a highly hygroscopic material, and the characteristics of the leather are greatly affected by the moisture content. During inclement conditions, a leather football begins to absorb water which results in a gain in weight, loss of pebble conformation, and increase in slipperiness. When this happens, there is a great loss in the durability and performance of the football.
A football pebble is created when an embossing plate with the reverse contour of the pebble shape compresses the leather down and leaves the impression of the pebble. At the bottom of the pebble--or the valley--the leather has been compressed the most. When the leather takes water into its fibers, the material swells, which causes the embossed areas to lose their definition. Saturated with water, the pebble-less surface exhibits a great loss of grippability due to the change of coefficient of friction.
The added water in the leather will also cause the ball to gain weight. An official size football is specified to weigh 14 to 15 oz. and can gain an additional 5 to 6 oz. when wet. With the added weight and change in the surface characteristics, the football cannot be thrown as far or as accurately. Also, the football becomes more difficult to hold onto. The overall result is a loss in performance.
One way to have a wet leather football perform like a dry leather football is to treat the ball with a water-repellent material. However, the treatment, whether before or after constructing the leather into a football, should be done so that it does not change the color, feel, size, weight, and performance of the ball. Under dry conditions, the water-repellent football should show no appreciable change in color, feel, size, or weight compared to an untreated football; that is critical.
In 1984, Rawlings Sporting Goods Co., a company owned by Figgie International, Inc., introduced a football with a foam padding inner layer. The football is known as the ST-5 and is described in U.S. Pat. No. 4,462,590 as having a softer feel due to the foam layer. U.S. Pat. No. 4,660,831 describes an improved version of Rawlings'"inflatable padded game ball", introducing a new padding material along with the mention of a new bladder construction. Although not disclosed in either of these patents, Rawlings introduced the ST-5 with a water-repellent feature. This water-repellent feature was accomplished by applying a treatment material to the outside of the leather. The method of application is believed to be the submersion of the assembled leather football in a fluorocarbonbased water-repellent treatment material. The submersion causes a complete encapsulation of the football. The result is a leather football that repels water better than an untreated leather football. This information was collected from third party sources, since neither of the Rawlings patents discloses the method or material for the water-repellent treatment.
Although the water-repellency level of the Rawlings football is excellent, this method of treatment affects at least two of the other physical properties--color and feel. Rawlings' method of water-repellent treatment darkens the leather and reduces the tacky feel of the football. Also, the Rawlings water-repellent treatment method is only effective on footballs which contain a layer of foam padding behind the leather cover. The foam padding is believed to act as a gasket on the backside of the leather which resists the absorption of water that may enter through the lace holes and stitch holes.